The present invention generally relates to a photographic camera and, more particularly, to a photographic camera of a type having a rangefinder and a built-in optical converter.
Although a lens interchangeable model is available, most rangefinder cameras have an objective lens assembly rigidly fixed to the camera body. This fixed objective lens assembly has a focal length generally within the range of 40 to 55 mm. and is generally referred to as a standard lens because of its similarity in optical capacity to the human eyes.
On the other hand, the rangefinder camera equipped with a built-in optical converter separately of the standard lens is well known to those skilled in the art. In this known photographic camera, the built-in optical converter generally serves to transmit a spatial image, formed by the standard lens of a target object to be photographed, to a photographic film on a scale different from that of the image projected onto the film solely by the standard lens, for example, on a magnified scale, when such built-in optical converter is brought into alignment with the optical axis of the standard lens. So far as magnification is involved, this optical converter is generally referred to as a telephoto converter.
In the known photographic camera of the type having the built-in optical converter, for example, the telephoto converter, a required switching mechanism for selectively bringing the telephoto converter into and out of alignment with the optical axis of the standard lens has heretofore been employed separately of a focus adjusting ring manipulatably mounted on the standard lens barrel.
Although the provision of the switching mechanism separately of the focus adjusting ring does not adversely affect the optical performance of the camera lens system as a whole, various inconveniences have been found in manipulating the camera. For example, with the conventional rangefinder camera of the construction described above, a photographer has to make a decision, prior to actual taking of a photographic picture of the target object, as to whether the target object should be shot with the standard lens system or whether the same should be shot with the telephoto lens system. Should the photographer decide to take a photographic picture of the target object with the telephoto lens system in the course of focus adjustment while the telephoto converter is held out of alignment with the optical axis of the standard lens, he has to interrupt the focusing operation to manipulate the switching mechanism, the consequence of which is that the photographer may loses a decisive shutter chance.
Even though the decisive shutter chance is of less importance, a similar disadvantage is often experienced that, while the photographer looks into the rangefinder with the camera held in one of his hands, he must move the other hand between the focus adjusting ring and the switching mechanism in chosing a suitable composition of the image of the target object within the framework of the viewfinder, thereby requiring a complicated handling procedure.